Prostate Cancer Screening and Prevention
The prostate is below the bladder (the hollow organ where urine is stored) and in front of the rectum (the last part of the intestines). Almost all prostate cancers are adenocarcinomas. These cancers develop from the gland cells in the prostate.
Other types of cancer that can start in the prostate include:
- Small cell carcinoma (small cell neuroendocrine carcinoma)
- Other neuroendocrine tumors (including large cell carcinoma)
- Transitional cell carcinoma
- Sarcomas
These other types of cancer are rare. If you are told you have prostate cancer, it is very likely to be an adenocarcinoma.
The number of prostate cancers diagnosed each year declined sharply from 2007 to 2014, coinciding with fewer men being screened because of changes in screening recommendations. Since 2014, however, the incidence rate has increased by 3% per year overall and by about 5% per year for advanced-stage prostate cancer.
How to get screened for prostate cancer
Prostate cancer can often be found early by testing for prostate-specific antigen (PSA) levels in a man’s blood. Another way to find prostate cancer is the digital rectal exam (DRE). For a DRE, the doctor puts a gloved, lubricated finger into the rectum to feel the prostate gland.
The American Cancer Society recommends that men have a chance to make an informed decision with their health care provider about whether to be screened for prostate cancer. The decision should be made after getting information about the possible benefits, risks, and uncertainties of prostate cancer screening. The discussion about screening should take place at:
- Age 50 for men who are at average risk of prostate cancer and are expected to live at least 10 more years
- Age 45 for men at high risk of developing prostate cancer. This includes African American men and men who have a first-degree relative (father or brother) diagnosed with prostate cancer at an early age (younger than age 65).
- Age 40 for men at even higher risk (those with more than one first-degree relative who had prostate cancer at an early age)
The screening tests below can be used to look for possible signs of prostate cancer, but these tests cannot tell for sure if you have cancer. If the result of one of these tests is abnormal, you will likely need a prostate biopsy to know for sure if you have cancer.
Prostate-specific antigen (PSA) is a protein made by cells in the prostate gland (both normal cells and cancer cells). The PSA level in blood is measured in units called nanograms per milliliter (ng/mL). The chance of having prostate cancer goes up as the PSA level goes up, but there is no set cutoff point that can tell for sure if a man does or does not have prostate cancer.
Many doctors use a PSA cutoff point of 4 ng/mL or higher when deciding if a man might need further testing, while others might recommend it starting at a lower level, such as 2.5 or 3. And some doctors might use age-specific cutoffs.
- Most men without prostate cancer have PSA levels under 4 ng/mL of blood. When prostate cancer develops, the PSA level often goes above 4. Still, a level below 4 is not a guarantee that a man does not have cancer. About 15% of men with a PSA below 4 will have prostate cancer if a biopsy is done
- Men with a PSA level between 4 and 10 (often called the “borderline range”) have about a 1 in 4 chance of having prostate cancer.
- If the PSA is more than 10, the chance of having prostate cancer is over 50%.
If your PSA level is high, you might need further tests to look for prostate cancer (see “If screening test results aren’t normal,” below).
Some companies now offer PSA test kits that let you collect a blood sample at home (typically from a finger stick) and then send it to a lab for testing. This could be more convenient for some men, and it might even allow some men to be tested who otherwise might not be.
However, a drawback with at-home testing is that it might not give a man the chance to discuss the pros and cons of prostate cancer screening with a health care provider before being tested, which could help him make an informed decision on whether to be screened.
Another important issue is that PSA blood test results are not black and white – that is, the test cannot tell for sure that you have (or do not have) prostate cancer. It is important to discuss the test results with a health professional who understands what the results mean for you.
The PSA level from a screening test is sometimes referred to as total PSA, because it includes all forms of PSA (described below). If you decide to get a PSA screening test and the result is not normal, some doctors might consider using different types of PSA tests to help decide if you need a prostate biopsy, although not all doctors agree on how to use these tests. If your PSA test result is not normal, ask your doctor about what it means for your prostate cancer risk and your need for further tests.
Percent-free PSA:
PSA occurs in 2 major forms in the blood. One form is attached (“complexed”) to blood proteins, while the other circulates free (unattached). The percent-free PSA (% fPSA), also known as the free/total PSA ratio (f/t PSA), is the ratio of how much PSA circulates free compared to the total PSA level. The percent-free PSA is lower in men who have prostate cancer than in men who do not.
If your PSA test result is in the borderline range (between 4 and 10), the percent-free PSA might be used to help decide if you should have a prostate biopsy. A lower percent-free PSA means that your chance of having prostate cancer is higher and you should probably have a biopsy.
Many doctors recommend a prostate biopsy for men whose percent-free PSA is 10% or less and advise that men consider a biopsy if it is between 10% and 25%. Using these cutoffs detects most cancers and helps some men avoid unnecessary biopsies. This test is widely used, but not all doctors agree that 25% is the best cutoff point to decide on a biopsy, and the cutoff may change depending on the overall PSA level.
Complexed PSA:
This test directly measures the amount of PSA that is attached to other proteins (the portion of PSA that is not “free”). This test could be done instead of checking the total and free PSA, and it could give the same amount of information, but it is not widely used.
There is no sure way to prevent prostate cancer. Many prostate cancer risk factors, such as age, race, and family history, cannot be controlled. But there are some things you can do that might lower your risk of prostate cancer.
The effects of body weight, physical activity, and diet on prostate cancer risk are not completely clear, but there are things you can do that might lower your risk.
Some studies have found that men with excess body weight have a higher risk of developing advanced prostate cancer or prostate cancer that is more likely to be fatal. Although not all studies agree, several have found a higher risk of prostate cancer in men whose diets are high in dairy products and calcium.
For now, the best advice about diet and activity to possibly reduce the risk of prostate cancer is to:
- Maintain a healthy weight.
- Be physically active.
- Follow a healthy eating pattern, which includes a variety of colorful fruits and vegetables and whole grains, and avoid or limit red and processed meats, sugar-sweetened beverages, and highly processed foods.
Taking any supplement could have both risks and benefits. Before starting vitamins or other supplements, talk with your doctor.
Some early studies suggested that taking vitamin E or selenium supplements might lower prostate cancer risk.
But a large study known as the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found that neither vitamin E nor selenium supplements lowered prostate cancer risk. In fact, men in the study taking the vitamin E supplements were found to have a slightly higher risk of prostate cancer.
Some early research has suggested possible benefits from soy proteins (called isoflavones) in lowering prostate cancer risk. Several studies are now looking more closely at the possible effects of these proteins.
Some drugs might help reduce the risk of prostate cancer.
5-alpha reductase is an enzyme in the body that changes testosterone into dihydrotestosterone (DHT), the main hormone that causes the prostate to grow. Drugs called 5-alpha reductase inhibitors, such as finasteride and dutasteride, block this enzyme from making DHT. These drugs are used to treat benign prostatic hyperplasia (BPH), a non-cancerous growth of the prostate.
Large studies of both drugs have tested if they might also be useful in lowering prostate cancer risk. In these studies, men taking either drug were less likely to develop prostate cancer after several years than men getting an inactive placebo.
When the results were looked at more closely, the men who took these drugs had fewer low-grade prostate cancers, but they had about the same risk of higher-grade prostate cancers, which are more likely to grow and spread. It is not clear if these drugs can lower the risk of dying from prostate cancer, as men in these studies had similar survival rates whether they took one of these drugs.
These drugs can cause sexual side effects such as lowered sexual desire and erectile dysfunction (impotence), as well as the growth of breast tissue in some men. But they can help with urinary problems from BPH, such as trouble urinating and leaking urine (incontinence).
They are not approved by the FDA to specifically to help lower prostate cancer risk, although doctors can prescribe them “off label” for this use. Men who want to know more about these drugs should discuss them with their doctors.
Some research suggests that men who take a daily aspirin might have a lower risk of getting and dying from prostate cancer. But more research is needed to show if the possible benefits outweigh the risks. Long-term aspirin use can have side effects, including an increased risk of bleeding in the digestive tract. While aspirin can also have other health benefits, most doctors do not recommend taking it just to lower prostate cancer risk.
Know the facts, risk factors, and cancer screening options. View and download education material below.